Cutter for sheet material



Dec. 6, 1955 c. c. PATTON 2,725,937

CUTTER FOR SHEET MATERIAL Filed Dec. 1, 1952' 2 Sheets Sheet l Dec. 6, 1955 c. c. PATTO N CUTTER FOR SHEET MATERIAL Filed Dec. 1, 1952 2 Sheets-Sheet 2 EL- m luvs/wok Cir/mes C. Pl? 7'ro/v 13y Jv/wwtm hwy/1% I? n'opusr.

United States Patentfitice 2,725,937 liatented Dec. 6, 1955 2,725,937 I CUTTER FOR SHEET MATERIAL Charles C. Patton, Port Caledonia, Nova Scotia, Canada Application December 1, 1952, Serial No. 323,377 4 Claims. c1. 164 -42 This invention relates to cutters for sheet material, either hand or power operated, for example, a cutter such as is described in my United States Patent No. 2,563,741, which was granted on August 7, 1951.

While a cutter such as is described in the patent mentioned above operates satisfactorily, l have made the discovery that the action of stripping the material from the blade can be greatly improved by provision of a stripperbar operated jointly by the cutter blade and a pivot-plate arranged to pivot about a point spaced from the pivot point of the blade so that the pivot-plate pivots in substantially the same plane as the blade.

According to the present invention a cutter comprises two bolster plates defining a cutting plane, a blade pivoted adjacent one end thereof at a first pivot point between the bolster plates so as to pivot forwardly for a cutting stroke, a pivot-plate pivoted adjacent one end thereof at a second pivot point spaced from the first pivot point so that the blade and the pivot-plate when pivoted move in substantially the same plane, a link pivotally joining the blade and the pivot-plate at points spaced lengthwise of the blade and the pivot-plate at substantial distances from the first and second pivot points, and a stripper-bar pivotally joining the blade and the pivot-plate and extending past the blade to engage the upper side of the work to be cut as the blade is raised following a cutting stroke, the stripper-bar being pivotally and slidably connected to'the pivot plate above and rearwardly of the second pivot point and being pivotally connected to the blade at a point on the blade above and rearwardly of the first pivot point.

In a preferred form of the invention the pivot-plate, which is'required in the operation of the stripper-bar, is another blade operating between bolster plates so that two cutters are provided, one of which can be set for one material while the other is set for another material. For example, one cutter can be operated with little or no clearance between the blade and the bolster plates as is desirable for cutting steel, while the other blade may have a suitable clearance from the bolster plates for cutting a crushable material such as asbestos.

It is also preferred in accordance with the present invention to provide a pair of set screws in the bolster plates each of which is adjustable into the space between the bolster plates and is located to make contact with the back edge of the blade when it is raised from its cutting position so that upon the back of the blade coming between the set screws the bolster plates are spread apart thereby tending to spread apart the cut material and so freeing the blade so that the material can be pushed ahead for a new cut. An important advantage of a stripper-bar in accordance with the present invention is that as the blade is raised from the cutting position the stripper-bar has a sliding motion against the material to be cut so helping in moving the material ahead for the next cut.

Another advantage of a cutter having a stripper-bar in accordance with the present invention is that the stripper-bar is etfective in stripping material from the blade as soon as the blade is raised from its full-cut position.

' in the embodiment of the The stripper-bar may be conveniently adjusted for various materials and can be arranged to operate with either blade invention in which the pivotplate is another cutter blade.

The invention will be further described with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a cutter according to the present invention Figure 2 is a cross sectional view of the cutter shown in Figure 1, taken on the line IIII at a larger scale;

Figure 3 is a cross sectional view of the cutter shown in Figure 1, taken on the line IIIIII at a larger scale; and

'Figui're 4 is a side elevation of the cutter shown in Figure 1 with the blades in full-cut position, and at a larger scale. 7

' Referring to the drawings, the cutter shown comprises two pairs of bolster plates ltlA, 10B and 11A, 113 which are fastened to base plates 12,13. The base plates 12, 13 are fastened to a base 14.

The bolster plates 10A, 10B and 11A, 11B are suitably bored to accommodate, pivot pins 15A and 15B upon which pivot the blades 16A and 1613 about suitable pivot holes formed therein. A handle member H is secured to the outer end of the blade MA by bolts 18. The handle H is connected to the blade ldB by links 17 which are pivotally connected to the blade 16B by a bolt 18.

A pair of stripper-bars 19 are pivotally connected to the blade MA by a bolt 20A (Figures 1 and 4) at a point above and rearwardly of the pivot point for the blade 16A formed by the pin 15A. The stripper-bars 19 are pivotally and slidably connected to the blade 16B by a bolt 20B at a point above and rearwardly (with respect to the blade 16A) of the pivot point of the blade 16B formed by the pin 15B. Provisionfor sliding of the links 19 relative to the blade 16B is made by slots 21 (Figure 4) in the links 19. 7 Two slots 21 are provided in each link 19 for which the reason will be explained below.

Two set screws 22A, 22B are provided near the rear of the bolster plates 10A, 103 in positions such that'when the blade 16A, is raised from its cutting position, as shown in Figure l, the back edge of the blade comes between the set screws 22A, 228 (see Figure 2) causing the bolster plates 10A and 1053 to be spread apart an amount dependent on the adjustment of the set screws 22A, 22B. This spreading apart of the bolster plates 10A, 10B is provided for by spring washers 29A, 29B on the pin 15A. As shown in Figures} and 4, theblade 16B has clearance with the bolster plates 11A, 11B as determined by a pair of washers 23A, 23B on the pin 15B. This clearance can be set by using washers 23A, 23B of different thicknesses and at the same time making a similar adjustment at the spacer 243 provided at the other end of the bolster plates 11A, 11B. A spacer 24A is also provided for the bolster plates 10A, 19B. The bolster plates 10A, 10B and 11A, 11B are of heavy material and are bevelled at a suitable angle over their working portions 25A, 25B and 26A, 2613. The bolster plates are undercut throughout their length by cuts 27A, 27B and 28A, ZSBto provide clearance for the blade and Waste cuttings.

The cutter shown in the drawings is set so that the blade 16A has the bevelled edges 25A, 25B of the bolster plates 10A, 10B pressed against it by the spring washers 29A, 2913 (Figure 2), while the blade 163 has the bevelled edges 26A, ZfiB of the bolster plates 11A, 11B spaced from it by the washers 23A, 233 (Figure 3). With these settings for the blades, the blade 16A can be used to cut such materials as steel, and the blade 168 can be used to cut such materials as asbestos sheeting. The handle H is shown on the bladeldA as required for cutting steel, but when cutting asbestos it may be connected directly to the blade 16B.

When cutting sheet metal with theblade '1'6A,'the sheet metal is placed across the bolster plates A, 103 with the blade 16A.in fully raised position. The cut is then commenced and as thecut proceeds, the sheet metal rides down on the bevelled edges 25A, 25B of the bolster plates 10A, 10B thereby slightly spreading the edges of the cut to prevent binding on the blade. 'At the same time the stripper-bars 19 move downwardto engage the sheet metal in the manner indicated in Figure 4. On completion of the cut the blade 16A is frictionally engaged by the edges of the cut in the sheet metal and, therefore, raising the blade 16A tends to raise the sheet metal from thebolster plates 10A, 10B causing even .greater frictional engagement between the blade 16A and the edges of the cut in the sheet metal. This frictional engagement tends to lift the sheet metal as the blade 16A is raised but the stripperbars engage the sheet metal firmly and at the same time, slide against the sheet metal in a direction to aid in moving the sheet metal toward the blade 16A for the next cut. The relative movement between the stripper-bars and the cutting edge of the blade 16A causes the sheet metal to be engaged by the stripper-bars. As the cutting edge of the blade -16A pivots to a vertical position, as shown in Figure 1, the stripper-bars provide a wiping action along the cutting edge of the blade 16A which causes the sheet metal to be stripped from the blade. As the blade 16A reaches a vertical position (Figures 1 and 2) its back edge presses between the set screws 22A, 22B causing the bolster plates to spread apart thus relieving binding between the sheet metal and the blade.

As shown in Figures 1 and 4, the stripper-bar 19 is provided with slots 21 for making pivotal connection to the bolt 208. The shape of the slot 21 provides for sliding of the stripper-bar 19 relative to the blade 16B so that the pivoting movement of the blades 16A and 16B will not be locked because of the stripper bar19 not being parallel to the link 17, as would be required for true parallelogram motion. In the case of the stripper bar beingvparallel to a line between the pins A and 15B, the slots 21 would not be required but less etfective stripping action would be provided at the cutting edge of the blade 16A.

The blade 16B is used for cutting sheet asbestos and like materials. The handle H is connected to the blade 16B and the stripper bars aremoved so that the bolts A, 20B engage the slot andhole which are shown as unoccupied in the drawings (Figures 1 and 4). When cutting asbestos, the action of the stripper bars 17 isthe same as that described in connection with c'utti'ng'sheet metal.

In constructing a cutter having stripper-bar action in accordance with the present invention, a single stripper-bar could be'used, but 'astr'ong'er cutter results by'using'a pair of stripper-bars as shown in the drawings. It is not necessary to have a blade 16B arranged to out another material, although this arrangement is of advantage. A plain pivotplate could be substituted for the blade 16B without interfering with the operation of the blade 16A and the stripperbars 19. If desired the cutter may be power-operated, for example, by a motor and speed-reducing gears.

What I claim as my invention is:

1. A cutter for sheet material comprising two bolster plates defining a cutting plane, a blade having a cutting edge and pivoted adjacent one end thereof at a first pivot point between the bolster plates so as to pivot forwardly with said cutting edge toward the bolster plates for a cutting stroke, a pivot-plate pivoted adjacent one end thereof at a second pivot point spaced from the first pivot point so that the blade and the pivot-plate when pivoted move in substantially the same plane, a link pivotally joining the blade and the pivot-plate at points spaced lengthwise of the blade and the pivot-plate at substantial distances from the first and second pivot points, and a stripper-bar pivotally joining the blade and the pivot-plate and extending past the cutting edge of the blade to the upper side of the sheet material work to be cut as the blade is raised following a cutting stroke, the stripper-bar being pivotally and slidably connected to the pivot plate above and rearwardly of the second pivot point and being pivotally connected to the blade at a point on the blade above and rearwardly of the first pivot point.

2. A cutter as defined in claim 1 comprising a pair of stripper-bars arranged with one on either side of the blade.

3. A cutter as defined in claim 1 in which the stripper bar has a slot-shaped opening through which it is pinned to the pivot plate so as to provide for sliding between the stripper bar and the pivot plate.

4. A cutter as defined in claim 3 in which the stripperbar makes an acute angle with a straight line drawn between the first and second pivotpoints so that the stripperbar slopes toward the cutting plane defined by the two bolster plates.

References Cited in the file of this patent UNITED STATES PATENTS 2,563,741 Patton Aug. 7, 1951 FOREIGN PATENTS 321,835 France June 5, 1902 

